Fiberglass reinforced composites

ABSTRACT

A fiberglass reinforced composite is provided with improved physical properties. The fiberglass reinforced composite incorporates core-shell rubber nanoparticles within the resinous binder of the composite and/or within a sizing composition coated directly onto the individual glass fibers.

The present application claims priority to U.S. provisional applicationNos. 61/679,196, filed on Aug. 3, 2012 and 61/727,453, filed on Nov. 16,2012, which are hereby incorporated by reference in their entireties.

BACKGROUND

Conventional asphalt roofing shingles are made by applying an asphaltcoating to a fiberglass web, embedding sand or other roofing granules inthe asphalt coating while still soft, and then subdividing the web soformed into individual shingles once the asphalt has hardened. Thefiberglass web is normally made from glass fibers bound together by asuitable resinous binder. In addition, a finely ground inorganicparticulate filler is normally included in the asphalt coating to reducecost, improve the heat distortion resistance of the shingle, and reduceasphalt UV degradation.

Commonly assigned U.S. Pat. No. 7,951,240, the entire disclosure ofwhich is incorporated herein by reference, indicates that the tearstrength of roofing shingles made in this way can be affected by thetype of particulate filler contained in the asphalt coating. Inparticular, this patent indicates that the tear strength of such roofingshingles may be compromised if hard fillers such as dolomite, silica,slate dust, high magnesium carbonate and the like are used.

It has been found that the physical properties of many types offiberglass reinforced polymer composites may be improved by includingcore-shell rubber nanoparticles in a resinous binder that is applied toglass fibers before they are combined with the polymer forming thematrix or body of a composite, such as a fiberglass mat for use inmaking shingles.

Moreover, it has also been found that glass fibers carrying thesecore-shell rubber nanoparticles can be easily made by including them inthe size that is applied to the fibers as they are made rather thanincluding them is a separate polymer binder subsequently applied to thefibers in a later manufacturing process, in which the previously-sizedglass fibers are used to make useful products.

SUMMARY

In some exemplary embodiments of the present invention, it has beenfound that the physical properties of a fiberglass reinforced compositemay be improved by incorporating core-shell rubber nanoparticles withinthe resinous binder of the composite.

In various exemplary embodiments of the present invention, thefiberglass reinforced composite comprises an improved roofing mat foruse in making asphalt roofing shingles. Some exemplary aspects of theimproved roofing mat comprise a fiberglass mat composed of multipleglass fibers and a resinous binder holding the individual glass fiberstogether, wherein the resinous binder includes rubber core-shellnanoparticles.

Moreover, in accordance with further exemplary aspects of thisinvention, it has been found that glass fibers carrying these core-shellrubber nanoparticles may be made by including core-shell rubbernanoparticles in the size that is applied to the fibers as they are maderather than, or in addition to, including the nanoparticles in aseparate polymer binder subsequently applied to the fibers in a latermanufacturing process.

Thus, exemplary aspects of this invention provide a fiberglassreinforced polymer composite is provided comprising a matrix polymer andglass fibers dispersed in the matrix polymer, wherein the surfaces ofthe glass fibers carry a coating of core-shell rubber nanoparticles.

In accordance with other exemplary aspects of the present invention,glass filaments and fiber for use in making a fiberglass reinforcedpolymer composite is provided. The glass filaments and fibers comprise aglass filament or fiber substrate carrying a coating of an aqueous sizecomposition, the aqueous size composition comprising a film-formingpolymer, an organosilane coupling agent and core-shell rubbernanoparticles.

Further exemplary aspects of the present invention also provide acontinuous process for making glass fibers comprising charging moltenglass through multiple orifices in a bushing to produce molten streamsof glass, allowing the molten streams of glass to solidify to formindividual filaments. The individual filaments may be coated with anincipient size composition containing a lubricant, a film forming resinand an organosilane coupling agent, and combined together to form thefiber. The process may further comprise applying a coating of core-shellrubber nanoparticles to the fiber.

Some exemplary embodiments provide fiberglass reinforced polymercomposite comprising a plurality of individual glass fibers fiberglassand a resinous binder, wherein core-shell rubber nanoparticles areincorporated within the resinous binder of the composite. The individualglass fibers may form a fiberglass mat held together by the resinousbinder. The resinous binder may include 0.1 to 20 wt. % rubbercore-shell nanoparticles, or 0.5 to 10 wt. % wt. % rubber core-shellnanoparticles, based on the total amount of resin in the binder. Theaverage particle size of the rubber core-shell nanoparticles may be 250nm or less. The resinous binder may be formed from a urea formaldehyderesin, an acrylic resin or a mixture thereof.

In some exemplary embodiments, the core of the rubber core-shellnanoparticles is made from a synthetic polymer rubber selected from thegroup consisting of styrene/butadiene, polybutadiene, silicone rubber(siloxanes), acrylic rubbers and mixtures thereof.

In other exemplary embodiments, the composite is an asphalt roofingshingle.

In various exemplary embodiments, an improved roofing mat for use inmaking asphalt roofing shingles is provided. The improved roofing matmay comprise a fiberglass mat composed of multiple glass fibers and aresinous binder holding the individual glass fibers together. Theresinous binder may include rubber core-shell nanoparticles. Theresinous binder may include 0.1 to 20 wt. % rubber core-shellnanoparticles, based on the total amount of resin in the binder. Theaverage particle size of the rubber core-shell nanoparticles may be 250nm or less. The resinous binder may be formed from a urea formaldehyderesin, an acrylic resin or a mixture thereof. The core of the rubbercore-shell nanoparticles may be made from a synthetic polymer rubberselected from the group consisting of styrene/butadiene, polybutadiene,silicone rubber (siloxanes), acrylic rubbers and mixtures thereof.

In yet other exemplary embodiments, an improved asphalt roofing shingleis provided comprising a fiberglass roofing mat composed of multipleglass fibers and a resinous binder holding the individual glass fiberstogether and an asphalt coating covering the fiberglass roofing mat. Theasphalt coating may include an inorganic particulate filler. The asphaltcoating may further contain roofing granules embedded therein. In someexemplary embodiments, the resinous binder of the fiberglass roofing matincludes rubber core-shell nanoparticles. The resinous binder mayinclude 0.1 to 20 wt. % rubber core-shell nanoparticles, or from 0.5 to10 wt. % rubber core-shell nanoparticles, based on the total amount ofresin in the binder. The average particle size of the rubber core-shellnanoparticles may be 250 nm or less. The resinous binder may be formedfrom a urea formaldehyde resin, an acrylic resin or a mixture thereof.The core of the rubber core-shell nanoparticles may be made from asynthetic polymer rubber selected from the group consisting ofstyrene/butadiene, polybutadiene, silicone rubber (siloxanes), acrylicrubbers and mixtures thereof. The asphalt coating may include 30 to 80wt. %, based on the entire weight of the filled asphalt, of an inorganicparticular filler selected from the group consisting of dolomite,silica, slate dust and high magnesium carbonate.

In various exemplary embodiments, a fiberglass reinforced polymercomposite is provided comprising a matrix polymer and glass fibersdispersed in the matrix polymer. The surfaces of the glass fibers maycarry a coating of core-shell rubber nanoparticles. In other exemplaryembodiments, the surfaces of the glass fibers carry a coating comprisinga mixture of core-shell rubber nanoparticles and a film-forming polymer.In other exemplary embodiments, the surfaces of the glass fibers carry afirst coating of an incipient size composition applied to the fibersduring fiber manufacture, the incipient size composition comprisingcore-shell rubber nanoparticles, a film-forming polymer and anorganosilane coupling agent. The incipient size composition may containa hydrocarbon wax.

In some exemplary embodiments, the glass fibers are made by combiningmultiple attenuated glass filaments together to form individual fibersand the incipient size composition is applied to the individual glassfilaments before they are combined.

In some exemplary embodiments, a second coating of a secondary incipientsize composition applied to the fibers during fiber manufacture afterthe individual glass filaments are combined, the secondary incipientsize composition comprising additional core-shell rubber nanoparticlesand a film-forming polymer.

The glass fibers may be made by combining multiple attenuated glassfilaments together to form individual fibers, wherein the surfaces ofthe glass fibers carry a first coating of an incipient size compositionapplied to the individual glass filaments before they are combined, theincipient size composition comprising a film-forming polymer and anorganosilane coupling agent, and further wherein the surfaces of theglass fibers carry a second coating of a secondary incipient sizecomposition applied to the fibers during fiber manufacture after theindividual glass filaments are combined, the secondary incipient sizecomposition comprising core-shell rubber nanoparticles and afilm-forming polymer.

The average particle size of the core-shell rubber nanoparticles may be250 nm or less. The core of the rubber core-shell nanoparticles may bemade from a synthetic polymer rubber selected from the group consistingof styrene/butadiene, polybutadiene, silicone rubber (siloxanes),acrylic rubbers and mixtures thereof.

In some exemplary embodiments, the core-shell rubber nanoparticles areapplied to the reinforcing glass fibers in the faun of a mixture of thecore-shell rubber nanoparticles and a film forming resin, and furtherwherein the mixture includes 0.1 to 20 wt. % rubber core-shellnanoparticles, 0.5 to 10 wt. % wt. % rubber core-shell nanoparticles,based on the total amount of film forming resin in the mixture.

In some exemplary embodiments, the fiberglass reinforced polymercomposite is roofing shingle.

In some exemplary embodiments, a glass filament for use in making afiberglass reinforced polymer composite is provided. The glass filamentmay include a glass filament substrate carrying a coating of anincipient size composition, the incipient size composition comprising afilm-forming polymer, an organosilane coupling agent and core-shellrubber nanoparticles.

In other exemplary embodiments, a glass fiber for use in making afiberglass reinforced polymer composite is provided. The glass fiber maycomprise a glass fiber substrate carrying a coating comprising a filmforming polymer and core-shell rubber nanoparticles.

The glass fiber may be composed of multiple glass filaments combinedtogether, the surfaces of the glass filaments carrying a first coatingof an incipient size composition applied to the filaments before beingcombined, the incipient size composition comprising a film-formingpolymer, an organosilane coupling agent and core-shell rubbernanoparticles.

The surfaces of the glass fiber carry a second coating of a secondaryincipient size composition applied to the fiber after the filamentsforming the fiber are combined, the secondary incipient size compositioncomprising additional core-shell rubber nanoparticles and a film-formingpolymer.

In other exemplary embodiments, a glass fiber is made by combiningmultiple attenuated glass filaments together to form the fiber, whereinthe surfaces of the glass fiber carry a first coating of an incipientsize composition applied to the individual glass filaments before theyare combined, the incipient size composition comprising a film-formingpolymer and an organosilane coupling agent. The surfaces of the glassfiber may additionally carry a second coating of a secondary incipientsize composition that is applied to the fiber after the individual glassfilaments are combined, the secondary incipient size compositioncomprising a film-forming polymer and core-shell rubber nanoparticles.

The average particle size of the core-shell rubber nanoparticles may be250 nm or less. Additionally, the core of the rubber core-shellnanoparticles may be made from a synthetic polymer rubber selected fromthe group consisting of styrene/butadiene, polybutadiene, siliconerubber (siloxanes), acrylic rubbers and mixtures thereof.

The core-shell rubber nanoparticles may be applied to the glassfilaments or fiber in the form of a mixture of the core-shell rubbernanoparticles and a film forming resin, and further wherein the mixtureincludes 0.1 to 20 wt. % core-shell rubber nanoparticles, based on thetotal amount of film forming resin in the mixture.

In yet further exemplary embodiments, a continuous process for makingglass fiber is provided that includes charging molten glass throughmultiple orifices in a bushing to produce molten streams of glass,allowing the molten streams of glass to solidify to form individualfilaments, coating the individual filaments with an incipient sizecomposition containing a lubricant, a film forming resin and anorganosilane coupling agent, and combining the individual filamentstogether to form the fiber. The process may further comprises applying acoating of core-shell rubber nanoparticles to the fiber.

The core-shell rubber particles may be applied to the glass fiber byincluding the core-shell rubber particles in the incipient sizecomposition.

In some exemplary embodiments, the core-shell rubber particles areapplied to the glass fiber by coating the glass fiber after it is formedwith a secondary incipient size composition comprising core-shell rubbernanoparticles and a film-forming polymer. The incipient size may alsocontains core-shell rubber nanoparticles.

The average particle size of the core-shell rubber nanoparticles may be250 nm or less and the core of the rubber core-shell nanoparticles maybe made from a synthetic polymer rubber selected from the groupconsisting of styrene/butadiene, polybutadiene, silicone rubber(siloxanes), acrylic rubbers and mixtures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention may be better understood by reference to the followingdrawings wherein:

FIG. 1 is a box plot of data illustrating the tensile strengths of twocertain fiberglass mats;

FIG. 2 is a box plot of data illustrating the tear strengths of twocertain fiberglass mats;

FIG. 3 is a box plot of data illustrating the tensile strengths of twocertain asphalt roofing shingles;

FIG. 4 is a bar chart showing the effect the core-shell rubbernanoparticles of this invention have on the burst strengths of glassfiber wound high pressure composite pipes made in accordance with thisinvention;

FIG. 5 is a graph showing the effect these core-shell rubbernanoparticles have on the interlaminar shear strength of the glass fiberwound high pressure composite pipes of FIG. 1; and

FIG. 6 is a graph showing the effect these core-shell rubbernanoparticles have on the tension exerted on the glass fibers used toform the glass fiber wound high pressure composite pipes of FIG. 4during their manufacture.

DETAILED DESCRIPTION Rubber Core-Shell Particles

Rubber core-shell particles are known articles of commerce described inseveral patents. For example, they are described in EP 2 053 083 A1, EP5 830 086 B2, U.S. Pat. No. 5,002,982, U.S. 2005/0214534, JP 11207848,U.S. Pat. No. 4,666,777, U.S. Pat. No. 7,919,549 and U.S. 2010/0273382,the disclosures of each being incorporated herein by reference in theirentireties. Generally speaking, they are composed of nanoparticleshaving a thermoplastic or thermosetting polymer shell and a core madefrom a synthetic polymer rubber such as styrene/butadiene,polybutadiene, silicone rubber (siloxanes) or acrylic rubbers.Generally, they have average particle sizes of about 250 nm or less,more commonly about 200 nm or less, about 150 nm or less or even about100 nm or less and a fairly narrow particles size distribution. They arecommercially available from a number different sources including KenakaCorporation of Pasadena, Tex.

Fiberglass Manufacture

Glass fibers are typically made by a continuous manufacturing process inwhich molten glass is forced through the holes of a “bushing,” thestreams of molten glass thereby formed are solidified into filaments,and the filaments are combined together to form a fiber or “roving” or“strand.” Glass fiber manufacturing processes of this type are known anddescribed in numerous patents. Examples include U.S. Pat. No. 3,951,631,U.S. Pat. No. 4,015,559, U.S. Pat. No. 4,309,202, U.S. Pat. No.4,222,344, U.S. Pat. No. 4,448,911, U.S. Pat. No. 5,954,853, U.S. Pat.No. 5,840,370 and U.S. Pat. No. 5,955,518, the disclosures of each beingincorporated herein by reference in their entireties. The rate at whichglass fibers are typically produced by such processes is on the order of4,000 to 15,000 feet per minute (about 1,220 to 4,572 meters perminute). It will therefore be appreciated that the time over which suchglass manufacturing processes occur, that is to say the period betweenthe time when the molten glass leaves the bushing and the time when thefully sized and formed glass fibers or strands are packaged, storedand/or used is very short, on the order of a fraction of a second.

The glass fibers can be made from any type of glass. Examples includeA-type glass fibers, C-type glass fibers, E-type glass fibers, S-typeglass fibers, ECR-type glass fibers (e.g., Advantex® glass fiberscommercially available from Owens Corning), Hiper-tex™, wool glassfibers, and combinations thereof. In addition, synthetic resin fiberssuch as those made from polyester, polyamide, aramid, and mixturesthereof can be also be included in the fiberglass mats of thisinvention. Similarly, fibers made from one or more naturally occurringmaterials such cotton, jute, bamboo, ramie, bagasse, hemp, coir, linen,kenaf, sisal, flax, henequen, and combinations thereof can also beincluded, as can carbon fibers.

Normally, an aqueous coating or “size” is applied to glass filamentsafter they have solidified but before they are contacted with therotating spindle for attenuation. Such sizes typically contain alubricant to protect the fibers from damage by abrasion, a film-formingresin to help bond the fibers to the polymer forming the body or matrixof the composite in which the fibers will be used, and an organosilanecoupling agent to improve the adhesion of the film-forming resin andmatrix polymer to the surfaces of the glass fibers. Although such sizescan be applied by spraying, they are typically applied by passing thefilaments over a pad or roller containing the size on its surfaces.

Sized glass fibers made in this way are used in the manufacture of avariety of different fiberglass reinforced polymer composites. In themajority of these manufacturing processes, the sized glass fibers arecombined with the matrix polymer forming the body or matrix of thecomposite before the glass fibers are arranged in final form in theproduct to be made. In another approach, the sized glass fibers arefirst assembled into a “perform, which is then impregnated with thematrix resin forming the body of the composite. This is the approachused in the manufacture of roofing shingles, in which the glass fibersare formed into a self-supporting web (perform) and the web so madecoated with asphalt, which then solidifies to form the final asphaltshingle product.

The fiberglass performs used in this approach are normallyself-supporting or at least coherent in the sense that the individualsized glass fibers will not separate from one another when exposed tothe stresses and forces occurring when the preform is manipulated and/orimpregnated with the matrix resin. For this purpose, the sized glassfibers are normally coated with an additional film forming resin to bondthe fibers together. For convenience, coating compositions used for thispurpose are referred to in this document as “binder sizes.” These bindersizes will be understood to be different from the size compositionsapplied to the glass filaments and fibers as part of their manufacturingprocess, which are referred to in this document as “incipient sizes” or“incipient size compositions.”

From the above, it should be clear that processes for making glassfibers and processes for using glass fibers are regarded in industry asseparate and distinct from one another. For this reason, process stepsor operations which occur during manufacture of glass fibers aretypically referred to as “in-line” steps or operations. In contrast,process steps or operations which occur during the use ofpreviously-made glass fibers, such as in the manufacture of fiberglassreinforced polymer composites, are typically referred to as “off-line”steps or operations. This terminology is used, for example, in theabove-mentioned U.S. Pat. No. 5,840,370, as well as U.S. Pat. No.8,163,664, U.S. Pat. No. 7,279,059, U.S. Pat. No. 7,169,463, U.S. Pat.No. 6,896,963 and especially U.S. Pat. No. 6,846,855. The disclosures ofeach of these patents being incorporated herein by reference in theirentireties. This terminology is also used in this disclosure.

Fiberglass Reinforced Polymer Composites

Various aspects of this invention also relate to making any typefiberglass reinforced polymer composite. Such products are well known inindustry, and are often referred to as “fiberglass reinforced plastics.”They are composed of glass reinforcing fibers and a polymer resinforming the body or “matrix” of the composite. For convenience, thesepolymers are sometimes referred to in this document as “matrixpolymers.” Also, in the context of this case, “polymer resin” and“polymer” are used in their broadest sense as including both manmadesynthetic resins as well as naturally occurring resinous materials suchas asphalt and the like.

The fiberglass reinforced polymer composites of this invention can bemade from any type of glass fiber. Examples include A-type glass fibers,C-type glass fibers, E-type glass fibers, S-type glass fibers, ECR-typeglass fibers (e.g., Advantex® glass fibers commercially available fromOwens Corning), Hiper-tex™, and combinations thereof.

The inventive fiberglass reinforced polymer composites can also includefibers made from materials other than glass, examples of which includesynthetic resin fibers such as those made from polyester, polyamide,aramid, and mixtures thereof. Similarly, fibers made from one or morenaturally occurring materials such cotton, jute, bamboo, ramie, bagasse,hemp, coir, linen, kenaf, sisal, flax, henequen, and combinationsthereof can also be included, as can carbon fibers. Similarly, inventivefiberglass reinforced polymer composites can also include non-fibrousfillers, examples of which include calcium carbonate, silica sand andwollastonite. Preferably, the fiberglass reinforced polymer compositesof this invention contain a combined total of no more than about 5 wt. %of non-glass fibers and fillers, based on the weight of all the fibersand fillers in the composite. More preferably, all or essentially all ofthe fibers in the fiberglass composites of this invention are glassfibers.

Similarly, the fiberglass reinforced polymer composites of thisinvention can be made from any resinous binder which has previously beenused or may be used in the future as the matrix polymer for making thebody or matrix of fiberglass reinforced plastic composites. Examplesinclude polyolefins, polyesters, polyamides, polyacrylamides,polyimides, polyethers, polyvinylethers, polystyrenes, polyoxides,polycarbonates, polysiloxanes, polysulfones, polyanhydrides, polyimines,epoxies, acrylics, polyvinylesters, polyurethane, maleic resins, urearesins, melamine resins, phenol resins, furan resins, polymer blends,alloys and mixtures thereof. Epoxy resins are especially preferred.

The amount of resinous binder that should be included in the fiberglassreinforced polymer composites of this invention can vary widely and anyconventional amount can be used. In some exemplary embodiments, in thecase of fiberglass mats, the amount of resinous binder will be about 10to 30 wt. %, more typically about 14 to 25 wt. % or even about 16 to 22wt. %, based on the weight of the fiberglass mat as a whole.

Fiberglass reinforced polymer composites can be made by a variety ofdifferent manufacturing techniques including simple coating andlaminating processes, but are most commonly made by molding. Twodifferent types of molding processes are commonly used, wet moldingprocesses and composite molding processes. In wet molding processes, theglass reinforcing fibers and the matrix polymer are combined in the moldimmediately prior to molding. For instance, fiberglass mats produced inaccordance with this invention may be made by a wet laid molding processin which wet chopped glass fibers, after being deposited onto a movingscreen from an aqueous slurry, are coated with an aqueous dispersion ofa resin binder which is then dried and cured. The formed non-woven webis an assembly of randomly dispersed, individual glass filaments boundtogether at their interstices by the resinous binder.

As stated above, the fiberglass mats of this invention include aresinous binder for holding the fibers together. For this purpose, anyresinous binder which has previously been used or may be used in thefuture for making fiberglass mats used in the manufacture of asphaltroofing shingles can be used as the resinous binder of this invention.Examples include urea formaldehyde resins, acrylic resins, polyurethaneresins, epoxy resins, polyester resins and so forth. Urea formaldehyderesins and acrylic resins are preferred, while mixtures of ureaformaldehyde resins and acrylic resins are even more preferred. In suchmixtures, the amount of acrylic resin is desirably about 2 to 30 wt. %,more desirably about 5 to 25 wt. % or even about 10 to 20 wt. % of thecombined amounts of urea formaldehyde resin and acrylic resin in thebinder, on a dry solids basis.

The amount of resinous binder that should be included in the fiberglassmats of this invention can vary widely and any conventional amount canbe used. Normally, the amount of resinous binder will be about 10 to 30wt. %, more typically about 14 to 25 wt. % or even about 16 to 22 wt. %,based on the weight of the fiberglass mat as a whole.

The physical structure of the fiberglass mat of this invention is notcritical and any physical structure which has previously been used, ormay be used in the future for making fiberglass mats for asphalt roofingshingles, can be used for making the fiberglass mat of this invention.For example, nonwoven webs of glass fibers as well as woven and nonwovenfiberglass fabrics or scrim can be used for making the fiberglass matsof this invention.

Most commonly, however, the fiberglass mat of this invention will bemade by a wet laid process in which wet chopped glass fibers, afterbeing deposited onto a moving screen from an aqueous slurry, are coatedwith an aqueous dispersion of a resin binder which is then dried andcured. The formed non-woven web is an assembly of randomly dispersed,individual glass filaments bound together at their interstices by theresinous binder.

Roofing Shingle

In some exemplary embodiments, an inventive asphalt roofing shingle ismade from the inventive fiberglass web, as described above, usingconventional production methods, i.e., by applying a molten asphaltcoating composition to the inventive fiberglass web, embedding sand orother roofing granules in this asphalt coating while still soft, andthen subdividing the web so formed into individual roofing shingles oncethe coating asphalt has hardened. Any production method may be used thathas been used, or used in the future, may be suitable in producing theinventive fiberglass mat and shingles. Any fiberglass mat that haspreviously been used, or may be used in the future, for making asphaltroofing shingles can be suitable for use in making the inventivefiberglass mats and shingles.

For this purpose, any asphalt coating composition which has previouslybeen used or may be used in the future for making asphalt roofingshingles may be suitable for use as the asphalt coating in thisinvention. As described in the above-noted U.S. Pat. No. 7,951,240, suchasphalt coating compositions include a substantial amount of inorganicparticulate filler. In addition, they can be made from a variety ofdifferent types and grades of asphalt and can also include variousdifferent optional ingredients such as polymeric modifiers, waxes andthe like. Any of the different grades of asphalt described there, aswell as any of the different inorganic particulate fillers and optionalingredients described there, may be suitable for making the roofingshingles of this invention.

In addition to these ingredients, the asphalt coating composition usedin this invention also includes an inorganic particulate filler. Forthis purpose, any inorganic particulate filler which is or becomes knownfor use in making asphalt roofing shingles can be used. For example,calcite (crushed limestone), dolomite, silica, slate dust, highmagnesium carbonate, rock dust other than crushed limestone, and thelike can be used. Concentrations on the order of 30 to 80 wt. %, basedon the entire weight of the asphalt coating, can be used althoughconcentrations of about 40 to 70 wt. % or even of about 50 to 70 wt. %are more typical.

As indicated above, some of these inorganic particulate fillers areknown to adversely affect the tear strength of asphalt roofing shinglesmade with these materials. In particular, inorganic fillers whichexhibit a high degree of hardness (i.e., a hardness greater than about 3Moh) such as dolomite, silica, slate dust, high magnesium carbonate,etc., are known to produce asphalt shingles having lower tear strengthsthan otherwise identical shingles made from softer inorganic filler suchas calcite (crushed limestone) and the like. Therefore, it is commonpractice in this industry to use calcite or other soft inorganicparticulate as the asphalt filler, as least when asphalt shingles ofsuperior tear strengths are desired. Tear strength is an importantproperty because it reflects the ability of an installed shingle toresist being destroyed or otherwise torn off a roof substrate by astrong wind. The same cannot be said for tensile strength, as tearstrength and tensile strength do not normally correlate with oneanother, at least in asphalt roofing shingles and the fiberglass matsfrom which they are made. Indeed, tear strength and tensile strength caneven be inversely proportional in some of these products.

Core-Shell Fiberglass Mats

In accordance with various aspects of this invention, it has been foundthat the poor tear strength problem of traditional asphalt roofingshingles can be overcome or otherwise obviated by incorporatingcore-shell rubber particles into the resin binder used to make thefiberglass mat from which the inventive asphalt roofing shingle is made.Therefore, in accordance with various aspects of this invention, asphaltroofing shingles exhibiting superior tear strengths can be produced eventhough hard inorganic fillers such as dolomite, silica, slate dust, highmagnesium carbonate, and the like are included in their asphalt coatingcompositions.

Once the asphalt coating composition of this invention is applied to theinventive fiberglass mat, a conventional roofing granule such as sand orthe like is applied to and embedded in this asphalt coating while stillsoft, such as in a conventional manner. The asphalt coating is thenallowed to harden, and the hardened web so formed is then subdividedinto individual roofing shingles.

It has already been proposed to use latexes of these rubber core-shellnanoparticles as binders for fiberglass mats. See, for example, theabove-noted EP 2 053 083 A1, EP 5 830 086 B2 and U.S. 2005/0214534. Insuch use, however, the fiberglass binder is composed entirely of theserubber core-shell nanoparticles. In contrast, in some exemplary aspectsof this invention, these rubber core-shell nanoparticles may beincorporated in small but suitable amounts as additives for improvingthe properties of a polymer resin which forms the body of the resinbinder. According to some aspects of the present invention, the amountof these rubber core-shell nanoparticles included in the resin binder ofthe fiberglass mat is about 0.1 to 20 wt. %, more typically about 0.5 to10 wt. % or even about 1 to 4 wt. %, based on the total amount of theother polymer resins in the binder, i.e., excluding the weight of therubber core-shell nanoparticles themselves.

It is also already known that the tensile strength of a solid polymermass (as reflected by its fracture toughness, peel strength and lapshear strength) can be enhanced by including these rubber core-shellnanoparticles in the mass as fillers. However, as indicated above, tearstrength and tensile strength do not correlate with one another in thefield of asphalt roofing shingles. This is shown in FIGS. 1 and 2, whichare box plots showing the tensile strengths and tear strengths offiberglass mats made with different conventional binders. See, also,FIG. 3, which is a similar box plot showing the tear strength of asphaltroofing shingles made with these different fiberglass mats. As shown inFIG. 1, the tensile strength of the mat made with binder A was betterthan the tensile strength of the mat made with binder B. In contrast,both the tear strength of the mat made with binder A (FIG. 2) and thetear strength of the asphalt roofing shingle made with binder A (FIG.3), were worse than the tear strengths of the mat and shingle made withbinder B. This shows that there is no direct correlation between tearstrength and tensile strength in asphalt roofing shingles and theirassociated fiberglass mats. This, in turn, demonstrates that theimproved tear strengths of the inventive mats and shingles is adifferent phenomenon from the improved tensile strengths shown in theprior art.

The shell of the rubber core-shell nanoparticles used in this inventioncan be formed from essentially any thermoplastic or thermosettingpolymer so long as it is compatible with the polymer used to form theresinous binder of the fiberglass mat used in this invention. And by“compatible” is meant that the polymer forming the shell does notadversely react with the resinous binder, either by adversely affectingits physical or chemical stability or generating obnoxious or unwantedby product.

Additional Fiberglass Reinforced Composites

In accordance with other exemplary embodiments, fiberglass reinforcedcomposites are formed by composite molding, wherein the glassreinforcing fibers and the matrix polymer are combined into a “prepreg”before being charged into the mold. Such prepregs can take the form ofself-supporting objects in which the glass fibers are randomly oriented,such as the fiberglass sheets or “veils” used to form asphalt shingles.In addition, they can also take the form of self-supporting objects inwhich the glass fibers are oriented in predetermined directions, such asthe three dimensional “skeletons” used to form load bearing products ofcomplex shape such as rocker arms for automobile suspensions. Suchprepregs can also take the form of pellets, pastilles or agglomeratescomposed of the matrix polymer containing randomly distributed choppedglass fiber.

Specific examples of molding processes that can be used to make thefiberglass reinforced polymer composites of this invention includeinjection molding, bladder molding, compression molding, vacuum bagmolding, mandrel wrapping, wet layup, chopper gun application, filamentwinding, extrusion molding, pultrusion, resin transfer molding andvacuum assisted resin transfer molding.

In accordance with some exemplary embodiments, the fiberglass reinforcedpolymer composite includes pressure-bearing vessels such as pipes(tubes) and tanks formed by filament winding or mandrel wrapping,especially products of this type in which the matrix polymer is an epoxyresin. Such products are well-known and described, for example, in U.S.Pat. No. 5,840,370 and U.S. Pat. No. 7,169,463, mentioned above. Asdescribed in these patents, such pressure bearing vessels are normallymade by winding a continuous glass fiber which has been impregnated withsome or all of the matrix polymer needed to form the vessel around arotating steel mandrel in specific orientations. Any additional matrixpolymer is then added, and the matrix polymer is then cured and themandrel withdrawn, thereby producing the product vessel. Alternatively,such products can be made by wrapping a preformed sheet or veil of glassfibers, preimpregnated with some or all of the matrix polymer needed toform the vessel, around a stationary steel mandrel followed by addingadditional matrix polymer if needed, curing the matrix polymer andwithdrawing the mandrel. As further described in these patents, theglass fibers used to form such products are normally sized during fibermanufacture with a binder size containing a lubricant, a film formingresin, and a coupling agent which is normally an organosilane.

In accordance with some exemplary aspects of this invention, core-shellrubber nanoparticles may be incorporated into the incipient size that isapplied to the glass fibers as they are made. It has been discoveredthat incorporating these nanoparticles onto the fibers in this way isnot only very convenient from a manufacturing standpoint but alsoeffective in producing glass fibers with improved reinforcing propertieswhen used in a variety of different fiberglass reinforced polymercomposite applications.

Generally speaking, it is desirable in accordance with this inventionfor the average particle size of the core-shell rubber particles used inthis invention to be 100 times smaller (i.e., less than 1%) of theaverage diameter of the glass reinforcing fibers to which they areapplied. Average particle sizes of 150 times smaller (i.e., less than0.67%) or even 200 times smaller (i.e., less than 0.5%) of the glassreinforcing fibers are interesting as well.

As explained above, it is known that the tensile strength of a solidpolymer mass (as reflected by its fracture toughness, peel strength andlap shear strength) can be enhanced by including these core-shell rubbernanoparticles in the mass as fillers. See, “Structure-PropertyRelationship In Core-Shell Rubber Toughened Epoxy Nanocomposites,” ADissertation by Ki Tak Gam Submitted to the Office of Graduate Studiesof Texas A&M University in partial fulfillment of the requirements forthe degree of Doctor Of Philosophy December 2003. However, as detailedabove, the tear strength of an asphalt roofing shingle and its tensilestrength do not correlate with one another. This demonstrates that theimproved tear strengths of the asphalt roofing shingles made inaccordance with this invention is a different phenomenon from theimproved tensile strengths shown in the prior art.

In this regard, it should be appreciated that the tensile strength of asolid polymer mass is understood to be a function of its cohesivestrength, i.e., the ability of the mass to hold itself together whenunder a tensile load. In contrast, the tear strength of an asphaltroofing shingle is understood to be a function of an entirely differentphenomenon, i.e., the ability of the binder size composition coating theglass fiber veil of the shingle to promote adhesion between the veil andthe subsequently applied asphalt coating (matrix polymer). Furthermore,when core-shell rubber particles are used to improve the tensilestrength of a solid polymer mass, enough of these nanoparticles are usedto fill the entire polymer mass. In contrast, a much smaller amount ofcore-shell rubber nanoparticles is used in this invention, since thesenanoparticles are present only on the surfaces of the glass fibersthemselves and are not distributed in the mass of matrix polymer formingthe body of the inventive fiberglass reinforced polymer composites.

In accordance with this invention, the core-shell rubber nanoparticlesof this invention can be applied to the glass reinforcing fibers anytimeprior to the application of the matrix polymer forming the body of theinventive fiberglass reinforced polymer composites. So, for example, thecore-shell rubber nanoparticles can be applied to the glass reinforcingfibers in a binder size after they are made and stored, in a separateapplication step as part of the manufacturing process for producing thefiberglass reinforced polymer composites of this invention.

Alternatively, they can be applied to the glass fibers “in-line” duringfiberglass manufacture as part of the glass fiber manufacturing processitself. Normally, this will be done by including these core-shell rubbernanoparticles in the incipient size composition applied to theindividual glass filaments used to form the glass fiber, before thesefilaments are combined together to form the fiber. Alternatively, thesecore-shell rubber nanoparticles can be applied to the glass fibers afterthey are formed in a separate aqueous size composition. For convenience,these separate size compositions are referred to in this document as“secondary incipient sizes.” In a third approach, both of theseprocedures can be used, some the core-shell rubber particles beingapplied to the individual filaments in the incipient size before theglass fibers are formed and the remainder being applied in a secondaryincipient size after the fibers are formed.

Regardless of which of these approaches is used, in-line applicationenables these core-shell rubber particles to be conveniently appliedduring glass fiber manufacture, which in turn eliminates the need for aseparate “off-line” process step during subsequent manufacture of theinventive fiberglass reinforced polymer composites. In addition, in-lineapplication of the core-shell rubber nanoparticles can reduce the amountof film-forming polymer that is ultimately applied to the glass fibers,at least when the nanoparticles are included in the incipient sizecomposition used during fiber manufacture. This is because, to promoteadhesion of the core-shell rubber nanoparticles to the glass fibers, thenanoparticles should be applied together with a film-forming polymer.Therefore, combining these nanoparticles with the incipient glass sizeeliminates the need for a second, subsequent film-forming resin coating.

As indicated above, the core-shell rubber nanoparticles of thisinvention may be applied to glass fiber or filament substrates togetherwith a suitable film forming resin. For this purpose, any film formingresin which has previously been used or may be used in the future as afilm forming resin in a glass fiber and/or filament size may be suitablefor use.

As appreciated in the art, it is conventional practice when selectingthe film forming resin to be used in an incipient size or a binder sizeto select a resin which is compatible with the matrix resin that will beused to make the fiberglass composite ultimately being produced. Forexample, if a particular fiberglass composite is to be made with anepoxy resin matrix, then a compatible epoxy resin will normally beselected as the film forming resin for the glass fiber size. This samecustomary practice is followed in accordance with this invention, i.e.,the film forming resin used in the size containing the core-shell rubbernanoparticles of this invention is desirably selected to be compatiblewith the matrix resin of the fiberglass reinforced polymer compositebeing produced

As further indicated above, this invention finds particular use inmaking fiberglass reinforced polymer composites from epoxy resins,because of the superior physical properties (e.g., ensile strength) andchemical resistance of these polymers. For this purpose, in someexemplary embodiments, it is desirable to select as the film formingresin in the size containing the core-shell rubber particles, a linearbisphenol A type epoxy resin of moderate molecular weight. In thiscontext, “moderate molecular weight” means a weight average molecularweight of about 10,000 to 250,000. Weight average molecular weights of15,000 to 100,000 or even 20,000 to 50,000 are preferred. Linearbisphenol A type epoxies are desirable because many fiberglassreinforced polymer composites, and especially those requiring highstrength and good chemical resistance, are made from linear bisphenol Atype epoxy matrix resins. These molecular weights are desirable, becausethe epoxy resin will not effectively form a film if its molecular weightis too high and will undergo unwanted crystallization in the coatingequipment if its molecular weight is too low.

In addition to linear bisphenol A type epoxies, modified epoxy resinscan also be used. For example, epoxy novolacs can also be used.

Specific examples of commercially available epoxy resins which areuseful as the film forming resin to be used together with the core-shellrubber nanoparticles of this invention are AD-502 epoxy aqueous emulsionfrom AOC, Neoxil 962/D aqueous emulsion from DSM, EpiRez 5003 fromMomentive, EpiRez 3511 epoxy emulsion from Momentive. Blends also areeffective, especially AD-502+EpiRez 5003 in a 95:5 ratio.

The amount of film forming resin that can be present in the aqueous sizecontaining the core-shell rubber nanoparticles of this invention canvary widely, and essentially any amount can be used that will provide aneffective coating composition. Typically, the amount of film formingresin will be about 60 to 90 wt. % of the aqueous size on a dry solidsbasis (i.e., excluding water). Concentrations on the order of about 65to 85 wt. %, or even 73 to 77 wt. %, on a dry weight basis arepreferred.

Sizes with Combination Particles

As indicated above, the aqueous size containing the core-shell rubbernanoparticles of this invention may also contain a film forming resin.While each of these ingredients can be separately supplied to andcontained in this aqueous size composition, in a particularlyinteresting embodiment of this invention these ingredients are combinedtogether in the emulsified particles contained in this aqueous sizecomposition.

Core-shell rubber nanoparticles are commercially available in a varietyof different forms. One such form is an organic emulsion of the rubbernanoparticles dispersed in neat (i.e., solvent free) liquid epoxy resin.Examples of these products include the Kane Ace™ MX line of CSR LiquidEpoxy Emulsions available from Kaneka Belgium NV. These liquidepoxy/rubber nanoparticle emulsions comprise stable dispersions of about25 to 40 wt. % CSR (core shell rubber nanoparticles) in variousdifferent kinds of liquid epoxy resin system including bisphenol-A typeliquid epoxy resins, bisphenol-F type liquid epoxy resins, epoxidizedphenol novolac type liquid epoxy resins, triglycidyl p-aminophenol typeliquid epoxy resins, tetraglycidyl methylene dianiline type liquid epoxyresins, and cycloaliphatic type liquid epoxy resins. They are well knownarticles of commerce which have been previously used for tougheningepoxy and other matrix resins, including matrix resins used for formingfiberglass reinforced polymer composites such as filament wound pipesand the like.

In this regard, it should be remembered that a significant differencebetween this invention and prior technology for making fiberglassreinforced composites containing core shell rubber nanoparticles isthat, in this invention, the core shell rubber nanoparticles are coatedonto the glass reinforcing fibers of the composite before these fibersare combined with the matrix resin forming the body of the composite.This is completely different from earlier technology in which the coreshell rubber nanoparticles are dispersed throughout the entire mass ofmatrix resin. Thus, a difference between this invention and priortechnology in connection with using these commercially available liquidepoxy core shell rubber nanoparticle emulsions is that, in thisinvention, these emulsions are used to form the incipient size that iscoated onto the glass fibers before these fibers are combined with thematrix resin. In contrast, in earlier technology, these emulsions areused to form the matrix resin itself.

These commercially available liquid epoxy/rubber nanoparticle emulsionsrepresent a convenient source of the core-shell rubber nanoparticles ofthis invention, because they already contain two major ingredients ofthe incipient sizes of this invention, i.e., the core shell rubberparticles and the epoxy resin film former.

According to some exemplary embodiments, before these commerciallyavailable liquid epoxy/rubber nanoparticle emulsion can be used to makethe incipient sizes of this invention, they are converted into aqueousemulsions. This can easily be done by using conventional high shearemulsification techniques. For example, a rubber nanoparticle aqueoussize composition in which the weight ratio of rubber nanoparticles toepoxy resin is 25/75 can be made by emulsifying an organic emulsioncontaining 25 wt. % rubber nanoparticles and 75 wt. % liquid epoxy resinusing conventional high shear mixing techniques and conventionalepoxy-suitable surfactants such as ethylene oxide/propylene oxide blockcopolymers.

The amount of core-shell rubber particles that will be applied to aglass fiber or filament substrate in accordance with this invention willtypically represent about 0.01 to 25 wt. % of the solids content of theaqueous size compositions in which they are contained. More commonly,the amount of core-shell rubber particles will be about 0.1 to 5 wt. %,about 0.3 to 2 wt. %, about 0.5 to 1.5 wt. %, or even about 0.7 to 1.3wt. % of these solids. Accordingly, the rubber nanoparticle aqueous sizecompositions of this invention will typically be made by combining atleast two different aqueous resin dispersions, one whose emulsifiedresin particles contain a combination of film forming resin andcore-shell rubber nanoparticles, the other whose emulsified resinparticles contain only the film forming resin.

Additional Ingredients

In addition to the film forming resin, the aqueous size compositioncontaining the core-shell rubber nanoparticles of this invention canalso contain various additional optional ingredients.

For example, these aqueous size compositions may contains about 5 to 30wt. %, more commonly about 8 to 20 wt. % or even about 10 to 15 wt. % ofan organosilane coupling agent based on the solids content. For thispurpose, any organosilane coupling agent that has previously been usedor may be used in the future for enhancing the bonding strength of afilm forming binder resin to a glass fiber substrate can be used in thisinvention. In addition, as in the case of the binder resin, theorganosilane coupling agent should be selected to be compatible with theparticular film forming binder resin being used.

Specific examples of useful organosilane coupling agents are SilquestA-1524 ureidosilane, Silquest A-1100 aminosilane, Silquest A-1387silylated polyazimide in methanol, Y-19139 silylated polyazimide inethanol from Momentive, Silquest A-174 methacryloxysilane, SilquestA-187 epoxy silane, Silquest A-1170 trimethoxy bis-silane, SilquestA-11699 triethoxy bis-silane, all from Momentive and Silquest A1120.Silquest A-1524 as well as blends of Silquest A-1387 and Silquest A-1100are preferred for use with epoxy resin film forming resins.

Another ingredient that can be included in the rubbernanoparticle-containing aqueous size compositions used in this inventionis a lubricant. Examples of commercially available lubricants that aresuitable for this purpose include Katex 6760 (also known as Emery 6760)cationic lubricant, PEG400 monooleate (PEG400 MO, Emerest 2646), PEG-200monolaurate (Emerest 2620), PEG400 monostearate (Emerest 2640), PEG600monostearate (Emerest 2662). Cationic lubricants such as Katex 6760 aretypically used in amounts from 0.001 to 2 wt, %, more typically 0.2 to 1wt. %, or even about 0.5 wt. %, of size solids. Meanwhile, PEGlubricants are typically used in amounts of 0.1 to 22 wt. %, moretypically about 1 to 10 wt. %, or even about 7 wt. % of solids content.

Yet another conventional lubricant that can be included in the rubbernanoparticle-containing aqueous size compositions used in this inventionis a wax. Any wax which has been or may be used as a lubricant wax in aglass fiber aqueous sizing composition can be used as the wax in therubber nanoparticle aqueous size compositions of this invention.Michelman Michemlube 280 wax is a good example. Concentrations on theorder of about 0.1 to 10 wt % of size solids are useable, whileconcentrations of about 2 to 6 wt % or even 4 to 5 wt % are preferred.

Still other conventional ingredients that can be included in the rubbernanoparticle-containing aqueous size compositions of this inventioninclude acetic, citric or other organic acid in an amount sufficient toefficiently hydrolyze the silanes that are present, which typicallyrequires a pH of about 4-6 in the case of Silquest A-1100. Final size pHwill typically be in the 5-6.5 range.

Other additives such as Coatosil MP 200 multifunctional epoxy oligomer,aqueous urethane polymers such as Michelman U6-01 or Baybond PU-403 fromBayer, Witco W-296 or W-298 from Chemtura or and the like can also beincluded in the rubber nanoparticle-containing aqueous size compositionsof this invention for their known functions in conventional amounts.

Water Content and Loadings

The rubber nanoparticle-containing aqueous size compositions of thisinvention are applied to their glass fiber and/or filament substrates ina conventional way using conventional coating equipment. Therefore, theyare formulated with sufficient amounts of water so that theirrheological properties are essentially the same or at least comparableto that of conventional aqueous sizes. Accordingly, these aqueous sizecompositions will typically contain a total solids content of about 2 to10 wt. %, more commonly 4 to 8 wt. % or even 5 to 7 wt. %, based on thetotal weight of the aqueous size composition.

In addition, these nanoparticle-containing aqueous size compositions arealso applied to their glass fiber and/or filament substrates inconventional amounts. For example, these size compositions will normallybe applied in amounts such that the LOI (loss on ignition) of the sizedglass fibers and filaments obtained is about 0.2 to 1.5%, more typically0.4 to 1.0% or even 0.5 to 0.8%. Inasmuch as the concentration ofcore-shell rubber nanoparticles in these sizes will typically be on theorder of about 0.3 to 2 wt. %, about 0.5 to 1.5 wt. %, or even about 0.7to 1.3 wt. % on a dry solids basis, this means that the amount of thesecore-shell rubber nanoparticles that will be applied to their glassfiber and/or filament substrates in terms of LOI will normally be about0.001 to 0.015%, more typically about 0.002 to 0.010% or even about0.0025 to 0.0080%.

WORKING EXAMPLES

In order to more thoroughly describe this invention, the followingworking examples are provided.

Example 1 and Comparative Example A

Two fiberglass mats were made by a conventional wet laid coating processin which wet chopped glass fibers, after being deposited onto a movingscreen from an aqueous slurry, were coated with an aqueous dispersion ofa resin binder and then dried and cured. The resin binders applied toboth webs were each prepared using a commercially-available acryliclatex (Rhoplex GL 720 available from Dow Chemical) and acommercially-available urea formaldehyde resin latex (FG 654A availableform Momentive). The amounts resins applied were selected so that theweight ratio of acrylic resin to urea formaldehyde resin in both binderswas the same on a dry solids basis (15/85) and further so that the totalamount of binder applied to each web was essentially the same. The resinbinder of Example 1 also included 1.7 wt. %, based on the combinedweights of urea formaldehyde and acrylic resins in the binder, of acommercially-available rubber core-shell nanoparticles, in particularKane Ace MX-113 rubber core-shell nanoparticles available from KenakaCorporation of Pasadena, Tex.

The fiberglass mats so obtained were then tested for tensile strengthand tear strength in the cross or transverse direction. Becausefiberglass mats and their associated asphalt roofing shingles aregenerally weaker in their transverse direction than in their machinedirection, tensile and tear strengths in the transverse direction give abetter indication of the overall strength of the product.

In addition to these tests, the tear strengths of these fiberglass matsin the transverse direction was also determined by a rock dusted matperformance test. In this test, each mat was first dusted with the sameamount of a powdered rock and then measured for tear strength in thetransverse direction. This test was used, because it provides a goodsimulation of the adverse effect on fiberglass mat properties that canbe caused by the inorganic particulate fillers contained in asubsequently applied asphalt coating. This rock dust mat performancetest was carried out three times for each sample, with the averagevalues obtained for each test being reported below.

The results obtained are set forth in the following Table 1:

TABLE 1 Tensile and Tear Strengths of Fiberglass Mats of Example 1 andComparative Example A Tear Trans- Transverse Transverse Retention(%):verse Tear (no Tear (rock (RD tear/ BW LOI Tensile rock dust) dusted)tear no RD) Comp 1.82 19.1 73 466 306 66 Ex A Ex 1 1.81 18.8 71 633 48877

In the above table, “BW” refers to basis weight, which is the weight ofcured mat (fiberglass plus cured binder) pounds per 100 square feet.Meanwhile, “LOI” refers to loss on ignition, which is a standard measurein this industry indicating the portion of the aqueous binder originallyapplied to the web, in percent, which remains on the web after thebinder has dried and cured. The total amount of binder applied to theweb after drying and curing, i.e., on a dry solids basis, can bedetermined by multiplying BW by LOI.

As can be seen from Table 1, the presence of rubber core-shellnanoparticles in the binder of Example 1 caused essentially no effect onthe tensile strength of the fiberglass mat made from this binder (thedifference in Table 1 is within the experiment error), but the tearstrength of this mat to increase, in the transverse direction relativeto the control fiberglass mat of Comparative Example A. In addition,Table 1 also shows that, while rock dusting caused a significantdecrease in the tear strength of both mats, this decrease was morepronounced in the case of Comparative Example A. Specifically, Table 1shows that the presence of these rubber core-shell nanoparticles enabledthe mat of Example 1 to retain 77% of its original tear strength,whereas the mat of Comparative Example A retained only 66% of itsoriginal tear strength, when both mats were rock dusted.

This data shows that the addition of these rubber core-shellnanoparticles improves the tear strength of fiberglass mats in thetransverse direction, not only in an “as-made” (uncoated) condition butalso in a simulated use condition.

Example 2 and Comparative Example B

Eight additional mats were prepared, four representing this inventionand four being controls in which no rubber core-shell nanoparticles wereused. These mats were made using the same procedures and ingredients asused in Example 1, except that the amount rubber core-shellnanoparticles included in the binders representing this invention was1.85 wt. %.

Each fiberglass mat obtained was then formed into an asphalt roofingshingle by coating the mat with an asphalt coating composition made fromof a coating asphalt, the asphalt coating composition also containing 65wt. % based on the asphalt coating composition as a whole of a calciteinorganic particulate filler.

The tensile strength of each roofing shingle in the machine directionwas measured, as was the tear strength of each roofing shingle in boththe machine and transverse directions. In addition, the total tearstrength of each roofing shingle was determined by adding the machineand transverse tear strengths together. Finally, these measured tear andtensile strengths were normalized by shingle weight.

The results obtained are set forth in the following Table 2.

TABLE 2 Tensile and Tear Strengths of Roofing Shingles of Example 2 andComparative Example B Machine MD Transverse Tensile Tear Total Tear CompEx B 192 1870 3317 Ex 2 185 2037 3615 % of Change −3.65 8.93 8.98

Table 2 shows that adding rubber core-shell nanoparticles to the binderof a fiberglass mat used to make an asphalt roofing shingle impartsessentially the same effect on the shingle as it imparts on the mat. Inparticular Table 2 shows that, like the fiberglass mats of Example 1,asphalt shingles made with these nanoparticles exhibit significantlygreater tear strengths in the transverse direction than control shinglesmade without these nanoparticles. In addition, Table 2 further showsthat these nanoparticles also cause a slight decrease in the tensilestrength of these shingles, in this case in the machine direction ratherthan in the transverse direction as reported in Example 1 above.

Example 3

In the following examples, filament wound high pressure composite pipeswere made by winding around a mandrel glass fibers having previouslybeen impregnated with a commercially available aqueous epoxy matrixresin dispersion. The winding so formed was then heated to cure theepoxy matrix resin and the mandrel then withdrawn to produce the finalproduct pipe.

The glass fibers used to make each composite were made by a conventionalglass fiber manufacturing process as described above in which theattenuated glass filaments, prior to being combined into fiber, werecoated with an incipient size. Three different experiments were done. Inthe first experiment representing the prior art, the incipient sizecontained no core-shell rubber nanoparticles. In the remaining twoexperiments, the incipient size contained 0.5 wt. % core-shell rubbernanoparticles and 1 wt. % core-shell rubber nanoparticles, respectively.

The amount of incipient size applied to each glass fiber is set forth inthe following Table 3, while the specific composition of each incipientsize is set forth in the following Table 4.

TABLE 3 Size Loadings % Rubber Yardage, Tex, Example Particles in SizeLOI, % Yards/pound g/kg Control 0 0.55 243.98 2033.20 4 0.5 0.57 251.741970.51 5 1.0 0.63 251.69 1970.94

TABLE 4 Chemical Composition of Incipient Sizes IngredientConcentration, wt. % solids Identity Function Control Example 1 Example2 Citric Acid pH control 0.53 0.53 0.53 Uredosilane Coupling 13.02 13.0313.04 agent Aqueous Epoxy 77.46 76.42 73.42 Resin Emulsion Aqueous 02.01 4.00 Nanoparticle Emulsion* PEG 400 Lubricant 3.89 3.92 3.92 WaxLubricant 4.69 4.70 4.70 Cationic Lubricant Lubricant 0.39 0.39 0.39*Aqueous emulsion of Kaneka's Kane Ace ™ MX-125 epoxy emulsioncontaining 75 wt. % epoxy resin and 25 wt. % core shell rubbernanoparticles

The filament wound composite pipes so obtained were subjected to twodifferent analytical tests. In the first, the burst strength of theproduct pipes obtained was determined. In the second, the interlaminarshear strength (ILSS) of the product pipes when exposed to boiling waterfor 500 hours was determined in accordance with the NOL Ring TestMethod, Accession No. AD0449719, Naval Ordinance Laboratory, White Oak,Md. In addition to these analytical tests, during manufacture of eachpipe, the tension generated on the glass fibers used to make the pipesduring the winding operation was determined and recorded. The resultsobtained are set forth in FIGS. 3-6.

As shown in FIG. 3, the burst strengths of the inventive product pipeswere about 8-11% greater than the burst strength of the control pipe.This shows that the core-shell rubber nanoparticles of this inventionprovide a substantial improvement in the mechanical properties of glassfiber reinforced polymer composites made in accordance with thisinvention.

Meanwhile, FIG. 4 shows that the core-shell rubber nanoparticles of thisinvention imparted essentially no adverse effect on the interlaminarstrength of the inventive product pipes after 500 hours of exposure toboiling water. This suggests that the core-shell rubber nanoparticles ofthis invention do not adversely affect the chemical resistance of theinventive glass fiber reinforced polymer composites in any significantway.

Finally, FIG. 5 shows that tension generated on the glass fibers duringthe winding operation used to form the inventive filament woundcomposite pipes was essentially unaffected by the core-shell rubbernanoparticles of this invention. This shows that the core-shell rubbernanoparticles of this invention do not adversely affect themanufacturing process used to produce the inventive glass fiberreinforced polymer composites in any significant way.

Although only a few embodiments of this invention have been describedabove, it should be appreciated that many modifications can be madewithout departing from the spirit and scope of this invention. Forexample, it is possible and even desirable in some instances to combinethe core-shell rubber nanoparticle technology of this invention withother technologies for making fiberglass reinforced polymer composites.

For example, the above-mentioned commonly assigned U.S. Pat. No.5,840,370 describes a process for making a glass/polymer prepreg inwhich application of some or all of the matrix polymer forming theultimate fiberglass reinforced polymer composite is applied “in-line” aspart of the glass manufacturing process. That technology can be combinedwith the technology of this invention by applying the core-shell rubbernanoparticles of this invention first, followed by impregnating thecoated glass fibers so formed with the matrix polymer of the polymercomposite second.

All such modifications are intended to be included within the scope ofthis invention and the related general inventive concepts, which are tobe limited only by the following claims.

1. A fiberglass reinforced polymer composite comprising a plurality of individual glass fibers fiberglass and a resinous binder, wherein core-shell rubber nanoparticles are incorporated within the resinous binder of the composite.
 2. The fiberglass reinforced polymer composite of claim 1, wherein said individual glass fiber form a fiberglass mat held together by the resinous binder.
 3. The fiberglass reinforced polymer composite of claim 1, wherein the resinous binder includes 0.1 to 20 wt. % rubber core-shell nanoparticles, based on the total amount of resin in the binder.
 4. The fiberglass reinforced composite of claim 1, wherein the average particle size of the rubber core-shell nanoparticles is 250 nm or less.
 5. The fiberglass reinforced composite of claim 1, wherein the resinous binder is formed from a urea formaldehyde resin, an acrylic resin or a mixture thereof.
 6. The fiberglass reinforced composite of claim 1, wherein the core of the rubber core-shell nanoparticles is made from a synthetic polymer rubber selected from the group consisting of styrene/butadiene, polybutadiene, silicone rubber (siloxanes), acrylic rubbers and mixtures thereof.
 7. The fiberglass reinforced composite of claim 1, wherein said composite is an asphalt roofing shingle.
 8. An improved roofing mat for use in making asphalt roofing shingles, the improved roofing mat comprising a fiberglass mat composed of multiple glass fibers and a resinous binder holding the individual glass fibers together, wherein the resinous binder includes rubber core-shell nanoparticles.
 9. The roofing mat of claim 8, wherein the resinous binder includes 0.1 to 20 wt. % rubber core-shell nanoparticles, based on the total amount of resin in the binder.
 10. The roofing mat of claim 8, wherein the resinous binder is formed from a urea formaldehyde resin, an acrylic resin or a mixture thereof.
 11. The roofing mat of claim 8, wherein the core of the rubber core-shell nanoparticles is made from a synthetic polymer rubber selected from the group consisting of styrene/butadiene, polybutadiene, silicone rubber (siloxanes), acrylic rubbers and mixtures thereof.
 12. An improved asphalt roofing shingle comprising a fiberglass roofing mat composed of multiple glass fibers and a resinous binder holding the individual glass fibers together, an asphalt coating covering the fiberglass roofing mat, the asphalt coating including an inorganic particulate filler therein, the asphalt coating further containing roofing granules embedded therein, wherein the resinous binder of the fiberglass roofing mat includes rubber core-shell nanoparticles.
 13. The asphalt roofing shingle of claim 12, wherein the resinous binder includes 0.1 to 20 wt. % rubber core-shell nanoparticles, based on the total amount of resin in the binder.
 14. The asphalt roofing shingle of claim 12, wherein the resinous binder is formed from a urea formaldehyde resin, an acrylic resin or a mixture thereof.
 15. The asphalt roofing shingle of claim 12, wherein the core of the rubber core-shell nanoparticles is made from a synthetic polymer rubber selected from the group consisting of styrene/butadiene, polybutadiene, silicone rubber (siloxanes), acrylic rubbers and mixtures thereof.
 16. The asphalt roofing shingle of claim 12, wherein the asphalt coating includes 30 to 80 wt. %, based on the entire weight of the filled asphalt of an inorganic particular filler selected from the group consisting of dolomite, silica, slate dust and high magnesium carbonate.
 17. A fiberglass reinforced polymer composite comprising a matrix polymer and glass fibers dispersed in the matrix polymer, wherein the surfaces of the glass fibers carry a coating of core-shell rubber nanoparticles.
 18. The fiberglass reinforced polymer composite of claim 17, wherein the surfaces of the glass fibers carry a coating comprising a mixture of core-shell rubber nanoparticles and a film-forming polymer.
 19. The fiberglass reinforced polymer composite of claim 17, wherein the glass fibers are made by combining multiple attenuated glass filaments together to form individual fibers, and further wherein the incipient size composition is applied to the individual glass filaments before they are combined.
 20. The fiberglass reinforced polymer composite of claim 17, wherein the surfaces of the glass fibers carry a second coating of a secondary incipient size composition applied to the fibers during fiber manufacture after the individual glass filaments are combined, the secondary incipient size composition comprising additional core-shell rubber nanoparticles and a film-forming polymer. 